The only downside is wasted time, and possibly wasted money if people get hooked into the productivity rabbit hole and end up spending ridiculous amounts of money on apps, books, gadgets and whatever else trying to be more productive.
I say this as someone who was probably like you once. I took a Big 5 personality test in my mid twenties that said that I had a low conscientiousness score which meant that I was pretty much destined to be a low earner as a high conscientiousness score is the trait most linked to high earners and achievement. What followed was probably a period of about seven years where I also tried all the meditation techniques whilst relentlessly trying to optimise my productivity, work and life, resulting in an inevitable burn out.
Following that, I like many others on here, have ended up just using a few text files for organisation and I am probably more organised than I have ever been. I use one file with day headings with tasks underneath that I plan to do on each day. And then I have other files for projects that just contain lists of tasks relating to that project. When I'm ready to work on one of those tasks I move them into the main file. It's that simple. I am happier and more focussed than I was using any of these other systems.
I make my text files in Obsidian, other people use org mode, some people use Google/Apple notes and others use Vim and plain text files. Even though it lead me to where I am now, I still look back and cringe at all the wasted time and energy I spent investigating and using all these other systems. I've done comments on reddit and elsewhere outlining my own overly convoluted systems that I might go back and delete in case someone stumbles on them and they lead people down the wrong path. KISS, Keep It Simple Stupid, really is the best strategy. And I suspect that also applies to regaining control with breathing which is why 4-4-4-4 works so well.
I remember the enthusiasm and confidence I felt when I thought I'd found some great method and how much I wanted to share it so don't let me stop you if that's what you want to do. But I'd wager in five years you'll have forgotten all about this, you'll be using something far simpler, and you will probably also cringe if you do remember it or come across an article like this from someone else.